UNC Eye at Roxboro

What is LASIK?

LASIK (laser in situ keratomileusis) is an outpatient surgical procedure used to
treat nearsightedness, farsightedness, and astigmatism. LASIK cannot reverse presbyopia,
the age-related loss of close-up focusing power, which mainly affects near vision.

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With normal vision, light rays focus directly on the retina.

With LASIK, the ophthalmologist uses a laser to reshape the cornea, which is located at the front of the eye. This improves the way the eye focuses light rays onto the retina, at the back of the eye, allowing for better vision.

It is important for anyone considering lASIK to have realistic expectations. LASIK allows many people to perform most of their everyday tasks without wearing corrective lenses. However, those hoping to achieve perfect vision and become completely free of the need to wear eyeglasses or contact lenses run the risk of being disappointed. Everyone develops the need to wear reading glasses in their 40s or 50s due to presbyopia. If your vision is fully corrected for distance with LASIK, you will need reading glasses to correct for presbyopia once it has developed. If you are nearsighted and do not yet need reading glasses, having LASIK may mean you will need reading glasses at an earlier age than had you not had laser eye surgery.

If you are having LASIK over the age of 40 and are interested in correcting your presbyopia (i.e., decreasing your dependence upon reading glasses), you may want to consider a strategy called monovision. This technique corrects your vision to allow for near or intermediate vision in one eye and distance vision in the other eye. This means that each eye is working independently instead of together.

For monovision, your dominant eye — the one you would use to look into the viewfinder of a camera — would become the distance eye and the other would be used for near vision. With this technique, the brain learns to adapt to eyes set to focus at different distances. Not everyone is comfortable with this difference in focus, especially those who spend a lot their time playing sports or do a lot of night driving.

However, many people find they adapt well to monovision when they try it out first, using contact lenses, before having LASIK. In fact, many preop LASIK patients over 40 are already using monovision with their contact lenses to decrease their dependence upon reading glasses, and are comfortable with it. Contact lenses are actually the best way to demonstrate monovision before surgery, as they most accurately replicate what the patient will see after surgery.

Nevertheless, some patients respond so positively to a “monovision demonstration” with trial frames (spectacles) during the preoperative evaluation that a contact lens trial is not necessary. If 20/20 vision is essential for your job or leisure activities, consider whether 20/40 vision would satisfy you. More than 90 percent of people who have LASIK achieve somewhere between 20/20 and 20/40 vision without eyeglasses or contact lenses.

Also, you would need to be comfortable with the possibility that you might need a second surgery (“retreatment”) in order to attain your desired results, or that you might need to wear glasses for certain activities, such as reading or driving at night. The greater your refractive error (that is, the greater your nearsightedness, farsightedness or astigmatism, or combination of these conditions), the more likely you would require retreatment or glasses.

It is important to discuss your lifestyle, including your work and recreational and leisure activities, with your prospective surgeon before deciding to go ahead with LASIK. Some work, sports and other activities are not compatible with LASIK.

Source: American Academy of Ophthalmology and the International Society of Refractive Surgery. Is LASIK for Me? A Patient’s Guide to Refractive Surgery. San Francisco, CA: American Academy of Ophthalmology and the International Society of Refractive Surgery, 2008. Print.